1. Field of the Invention
The present invention relates to an image generation apparatus, method and recording medium, and more particularly, to an image generation apparatus, method and recording medium for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space.
2. Description of Related Art
In recent years, when a three-dimensional body such as a character is displayed in a virtual space in a computer game etc., a more realistic game is realized by showing the shadow of the character on topographical features etc. Conventionally, two methods are known to express the shadow of a character in a computer game etc.; a method of expressing the shadow by substituting a simple shape such as a circle for it and a method of expressing the shadow by setting a desired light source in a virtual space of the computer game and calculating influences of the light from this light source on the character etc. in real time.
The former method expresses the shadow of the character using a simple shape such as a circle or ellipse and has a merit of imposing less load on the computer (CPU), whereas this method has a problem of having difficulty to express a natural shadow with respect to changes of the character""s action. On the other hand, the latter method calculates the influences of light from the light source in real time and can therefore express the shadow in greater detail, but has a problem of imposing heavy burden on the CPU.
In the case of a three-dimensional body such as a character having legs, even if the character moves such as spreading his/her legs apart, the size (scale) of the shadow according to the conventional art remains unchanged. Furthermore, in the case of a three-dimensional body such as a character having a lumbar part, the conventional art displays the shadow like a circle right beneath the lumbar part. This causes a problem of having difficulty to express the shadow in accordance with the motion of the character.
The present invention has been achieved to solve the problems described above and it is an object of the present invention to provide an image generation apparatus, method and recording medium capable of expressing natural shadows according to changes of motions of a character and creating shadows with less load on the CPU.
It is another object of the present invention to provide an image generation apparatus, method and recording medium capable of generating lively shadows according to motions of the character even when the character has a motion such as spreading his/her legs apart.
According to a first aspect of the present invention, there is provided an image generation apparatus that generates a shadow object to express the shadow of a three-dimensional body set in a virtual space, comprising: a topographical object on which the shadow object of the three-dimensional body is displayed; and shadow object generating means for generating a shadow object to be displayed on the topographical object according to a positional relationship between the three-dimensional body and the topographical object.
According to a second aspect of the present invention, there is provided an image generation apparatus that generates a shadow object to express the shadow of a three-dimensional body set in a virtual space, comprising: a topographical object on which the shadow object of the three-dimensional body is displayed; and shadow object generating means for generating a shadow object to be displayed on the topographical object according to a speed relationship between the three-dimensional body and the topographical object.
According to a third aspect of the present invention, there is provided an image generation apparatus that generates a shadow object to express the shadow of a three-dimensional body set in a virtual space, comprising: a topographical object on which the shadow object of the three-dimensional body is displayed; and shadow object generating means for generating a shadow object to be displayed on the topographical object according to the distance between a predetermined observing point in the virtual space and the three-dimensional body.
According to a fourth aspect of the present invention, there is provided an image generation method for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space, wherein a shadow object of the three-dimensional body to be displayed on a topographical object is generated according to a positional relationship between the three-dimensional body and the topographical object.
According to a fifth aspect of the present invention, there is provided an image generation method for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space, wherein a shadow object of the three-dimensional body to be displayed on a topographical object is generated according to a speed relationship between the three-dimensional body and the topographical object.
According to a sixth aspect of the present invention, there is provided an image generation method for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space, wherein a shadow object of the three-dimensional body to be displayed on a topographical object is created according to the distance between a predetermined observing point in the virtual space and the three-dimensional body.
According to a seventh aspect of the present invention, there is provided a recording medium storing a computer-readable program to execute an image generation method for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space, wherein a shadow object of the three-dimensional body to be displayed on a topographical object is created according to a positional relationship between the three-dimensional body and the topographical object.
According to a eighth aspect of the present invention, there is provided a recording medium storing a computer-readable program to execute an image generation method for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space, wherein a shadow object of the three-dimensional body to be displayed on a topographical object is created according to a speed relationship between the three-dimensional body and the topographical object.
According to a ninth aspect of the present invention, there is provided a recording medium storing a computer-readable program to execute an image generation method for generating a shadow object to express the shadow of a three-dimensional body set in a virtual space, wherein a shadow object of the three-dimensional body to be displayed on a topographical object is created according to the distance between a predetermined observing point in the virtual space and the three-dimensional body.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.